Control system for flywheel equipped machines



June 30, 1959 G. F. DIODATl 2,392,519

CONTROL SYSTEM FOR FLYWHEEL EQUIPPED MACHINES Filed June 21, 1954 2 Sheets-Sheet 1 *iM [NIDR G. F D/ODA T/ A rroR/vl-i June 30, 1959 CONTROL Filed June 21, 1954 G. F. DIODATI SYSTEM FOR FLYWHEEL EQUIPPED MACHINES 2 Sheets-Sheet 2 A 7' TORNEY United States Patent CONTROL SYSTEM FOR FLYWHEEL EQUIPPED MACHINES Giacomo F. Diodati, Newton Junction, N.H., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Application June 21,1954, Serial No. 438,216

4 Claims. (Cl. 192-.02)

This invention relates to safety control systems for machines such as metal working multi-slide machines.

In various types of material working machines, the drive shafts are usually powered by electrical motors, assisted by flywheels and provided with clutches to connect the drive shafts to the tool supporting units which are to be actuated to form articles of predetermined contours from metal stock. Although these machines are intended to be foolproof and free of jamming of formed parts or material, it has been found that on rare occasions, conditions such as these may cause damage to the machine. Furthermore, these chances are multiplied by the number of operations performed by each machine. For example, in a multi-slide machine there may be as many as five forming operations produced by the tool supporting slides operating in timed relation with each other to perform their individual operations on material. In this instance, any one or group of the five slides could become jammed causing possible serious damage to the machine and perhaps to the operator. Although these undesirable happenings are not frequent in their occurrence, the mere fact that they may occur is disturbing.

The object of the present invention is a safety control capable of preventing damage during the occurrence of any of these undesirable conditions.

With this and other objects in view, the invention comprises a safety control system for material working machines including a motor driven shaft connected through a clutch to driven means for a material working unit, the. safety control system including. means to deenergize' the motor if the speed of the drive shaft is reduced beyond a safe operating speed.

More specifically, the safety control system includes a brake mechanism on the drive shaft which is released during; normal operation of the machine but which is applied to stop the driving mechanism the moment" an undesirable condition exists in the machine. There is also a centrifugal switch driven by the drive shaft to hold the motor energized during normal speed of the drive shaft and adapted toopen the circuit to the motor upon reduction of the drive shaft below a safe operating speed.

Other objects and advantages will be apparent from the following detailed description when considered in conjunction with the accompanying drawings, wherein:

Fig. 1 is a front elevational view of a machine selected to illustrate the invention, and

Fig. 2' isa schematic illustration of the electrical and pneumatic. features of the safety control system.

The machine indicated generally at in Fig. 1 is what is known as amulti-slide machine having a predetermined number of tool supporting slides, one of which is. indicated at 11, driven in timed relation with. each other to 'formarticles of given contours from metal stock fed in the conventional manner to the machine. Machines of this type are well known commercially and it is not believed necessary to show in. detail the. entire machine 2,892,519 Patented June 30, 1959 or the various operating slides thereof in order to illustrate the invention.

The safety control system is associated directly with the drive mechanism of this machine or with any machine which is to be controlled thereby. The power means begins with an electric motor 12 which drives the gears 3, 4, 5 and 6 of a speed reducing unit 14. In the present embodiment of the invention the speed reducing unit 14 is connected to a drive shaft 16 through a clutch having members 15 and 17. The clutch member 17, which interengages gear 6, is free to rotate on a sleeve 7 which is keyed at 8 to the shaft 16. The clutch member 15 is fixedly mounted on the sleeve 7 and both clutch members have the conventional teeth 9 for interengagement when the sleeve 7 and the clutch member 15 are moved to the left into closed or operated positions, to operatively connect the drive shaft 16 with the power means 12 and 14.

By the schematic illustration in Fig. 2, it is possible to show the various features of the invention without showing in detail how the various units are mounted or how the shafts and other moving parts are supported. The gear 17, constituting a part of the clutch, is free to rotate on the sleeve 7 but is held against axial movement by suitable stationary means (not shown). Therefore, the sleeve 7 is free to move in the clutch member 17, through actuation of the lever 30, to move the clutch member 15 into and out of engagement with the clutch member 17, without disturbing the interengagement of the clutch member 17 with the gear 6. When the clutch members 15 and 17 are engaged the driving connection is completed between the gear 6 and the shaft 16. When the clutch 15-17 is open, with the clutch member 15 moved free of the clutch member 17, the driving connection with the shaft is broken.

The drive shaft 16 is journalled in suitable bearings and has its right end connected through pulleys 18 and 19 and a belt 20 toa centrifugal switch 21. The other end of the shaft supports a flywheel 23 which is fixed to the shaft and also a brake drum (not shown) which is a part ofa conventional pneumatic brake 24. The details of this type of brake are well known commercially and it is believed unnecessary to show them in order to illustrate the invention. A housing 25 encloses gears 16' and 26' operatively connecting the drive shaft 16 with a driven shaft 26. The shaft 26 is journalled' in bearings 27 and has its ends (not shown) disposed in housings 28 where they are operatively connected to mechanisms for actuating the slide 11 and other slides of the machine to. carry out the various forming operations. The sleeve 7 and clutch member 15 are actuated into open and closed positions by the conventional hand operated lever 30 pivoted at'31and adapted to reciprocate a rod 32 carrying a yoke 33 positioned in engagement with a clutch collar 34 fixed to the sleeve 7. The rod 32 is utilized to actuate a single pole double throwswitch 36 mounted in alignment therewith. The switch is normally urged into engagement with its right contact when the lever 30 is moved into the solid line position (Fig. 2') to release the clutch and is held in this position through the normal closing of the clutch. The left contact is used only during the manual jogging of the machine as will be described hereinafter. A normally closed exhaust valve 37 is mounted tobe actuated by the 1ever30 into open position'when in the clutch releasing. position.

The schematic illustration in Fig. 2 shows the three lines. 40, representing the motor circuit including, a main set of switches 41, and a series of contacts 42 of a relay 43. The lines 40 representing the motor circuit may be connected toa 440 v. supply and through the aidof a transformer 39 connected to two of. the lines of the motor circuit, a v. supply isprovided for lines 44- and 45.

Fig. 2 illustrates the normal position of the safety control when the machine is unoperated. To start the machine, a start switch 46 is momentarily closed and a switch 47, bypassing the centrifugal switch 21, is closed and held closed first to operate a relay 48 and holdit operated until the motor 12 is energized and increases its speed of rotation of the drive shaft 16 to a known safe speed at which time switch 21 will be closed. When switches 46 and 47 are closed, a circuit is completed from line 44 at connection 49 through relay 48, start switch 46, normally closed stop switch 50, switch 47 to line 45 at connection 51. Switch 52 is an emergency stop switch located at a convenient position away from the switches 46, 47 and 50 to serve in stopping the machine when desired. Completion of this circuit energizes relay 48, requiring only momentary closing of switch 46 and resulting in closing of contacts 54 and 55. Contact 54, when closed, completes a locking circuit through the relay 48 between connections 56 and 57.

The centrifugal switch 21 is illustrated in its open position. When the switch is driven at a speed comparable to the safe speed of the drive shaft 16, the actuating weights 58 thereof through centrifugal force, will move the switch 21 into closed position. Switch 47 thereby serves as a bypass switch for the centrifugal switch 21 until the drive shaft 16 has reached the desired safe speed.

When contact 55 is closed, a circuit is completed from line 44 to solenoid valve 61, line 60, connections 62 and closed contact 55 to line 45. At the same time, a pilot light 63 is illuminated through the completion of a circuit at connections 64 and 65.

The valve 61 is connected to a fluid supply line 66 where air under pressure is continuously supplied to the valve and controlled by the valve with respect to a pressure switch 67 and the air operated brake 24. When the valve 61 is de-energized as shown in Fig. 2, air is free to pass under pressure according to the solid line arrows through fluid lines 69 and 70 to the pressure switch 67 and the 'brake 24. When this happens, switch 67 opens a line 71 between a contact 72 of switch 36 and relay 43. At the same time, a braking force through the actuation of the brake 24 is applied to the drive shaft 16. When the solenoid valve 61 is energized, lines 69 and 70 are cut off from the supply line 66 and if the exhaust valve 37 is actuated into its open position, air under pressure may escape from the brake 24 and the pressure switch 67 in the directions of the dotted arrows so that the brake will become ineffective and the switch 67 will close line 71. The exhaust valve is positioned to be moved to its open position by the clutch lever 30 during the first portion of the levers movement to engage the clutch 15-17 and before the clutch is engaged.

Considering now the operation of the safety control system, let it be assumed that the machineis at rest as illustrated schematically in Fig. 2. To bring about operation of the apparatus, the motor 12 would be deenergized and the clutch lever 30 moved clockwise far enough to hold the exhaust valve operated into its opened position but not far enough to move the switch 36 free of its contact 72 by the clutch rod 32. One of the important functions of the safety control system is to permit manual jogging of the machine with the conventional lever bar without any possibility of the motor 12 being energized. This is accomplished by moving the clutch lever 30 to its extreme clockwise position where it will be held by a spring 75, holding valve 37 open and moving switch 36 from contact 72 to contact 76.

.This opens the relay circuit at contact 72 and completes a circuit through solenoid value 61 to energize it to cut off air supply and permit exhausting of'lines 69 and 70. The air brake is free, permitting safe manual jogging of the machine. To start the machine for regular operation, the operator moves the clutch lever 30 counterclockwise contact 76 to contact 72 but not far enough to free valve 37 to close. The operator closes switch 46 momentarily and closes switch 47 and holds it closed to bypass the centrifugal switch 21 until the motor 12 is energized and allowed to reach its top speed.

At the initial closing of switches 46 and 47, it will be observed, by viewing Fig. 2, that the circuit through relay 48 is completed, its contacts 54 and 55 are closed and the relay is locked in the circuit through its contact 54. Contact 55, when closed, causes energization of solenoid valve to cut off air supply line 66 and open linm 69 and 70 to the opened exhaust valve 37. Air under pressure is exhausted from switch 67 while valve 37 is held open, allowing switch 67 to close, and from brake 24 to remove the braking force from the drive shaft 16. As soon as switch 67 is closed, relay 43 is energized to close the motor circuit. When the motor reaches its top or running speed, the unit 14 drives the clutch members 1517 at a speed required for the operating speed of the shaft 16. The shaft drives the centrifugal switch 21, and as the switch is set to be operated into-closed position and remain closed until the speed of the drive shaft is reduced below a safe speed. The switch 47 may be released at this time.

The machine remains in this operating condition until something occurs to disturb any of the slides or units, receiving their operating forces from the drive shaft 16, causing an unusual torque on the shaft to decrease its speed. The moment this occurs, the centrifugal switch 21 will open the circuit to relay 48, de-energizing the relay and causing its contacts 54 and 55 to open. Opening of contact 55 will cause immediate de-energization of relay 43 to open switch 42 to the motor 12 and will also de-energize the lamp 63 and the solenoid valve 61. When the valve 61 is de-energized, the exhaust line through valve '37 is closed and line 69 and 70 are opened to the fluid supply line 66 to cause immediate opening of pressure switch 67 and actuation of the fluid brake 24 to stop rotation of the drive shaft 16. This occurs without the necessity of constant attention of the operator or, without the necessity of operating the clutch into the open position which would require more time than is utilized for the function of the safety control system in de-energizing the power means and bring to a stop the drive shaft with all the associated mechanisms.

It is to be understood that the above described arrangements are simply illustrative of the application of the principles of the invention. Numerous other atrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. A safety control for a material working machine having a drive shaft adapted for operable connection through a clutch, actuated by a movable lever, to a motor, disposed in an electrical motor circuit, to drive the shaft normally at an operating speed when the motor circuit is closed, the safety control comprising a normally inactive fluid operable brake unit for the drive shaft adapted to be actuated by fluid under pressure to apply a braking force to the shaft to stop the shaft, a line to direct a fluid under pressure to and from the brake unit, an exhaust fluid line including a normally closed exhaust valve aotuable into open position by the lever during movement of the lever to actuate the clutch into connecting position, a supply line for a fluid under pressure, a solenoid valve, disposed in an electrical c1rcuit, when unoperated opening the supply fluid line to the line of the brake unit, to free fluid under pressure from the supply line to flow through the 1111610 the brake unit to cause the brake unit to apply a braking force to the shaft to stop rotation of the shaft, and closing the exhaust fluid line, means operable to close the electrical circuit of the solenoid valve to causeena distance, suflieient to I free switch 36 to move from 75 ergization of the solenoid valve to close the supply fluid aeoaare line to the brake unit line and open the exhaust fluid line to the brake unit line to render the brake unit inactive with respect to the shaft, a normally closed pressure switch connected to the brake unit line and operable into open position by fluid under pressure in said line operating the brake unit, and an electrical control cirouit including the pressure switch, means energizable to close the motor circuit when the pressure switch is closed and a normally closed switch actuable by the lever to open the control circuit to maintain the motor de-en ergized while the lever holds the exhaust valve open to the brake unit to condition the machine for safe manual jogging.

2. A safety control for a material working machine having a drive shaft connected by a lever operable clutch to a motor, disposed in an electrical circuit, to drive the shaft normally at an operating speed when the clutch is operated into connecting position, the safety control comprising a normally inactive brake unit for the drive shaft adapted to be actuated by fluid under pressure to apply a braking force to the shaft to stop the shaft, a supply line for a fluid under pressure, an exhaust fluid line, a line to direct fluid under pressure to and from the brake unit, a solenoid valve, disposed in an electrical circuit, when unoperated opening the supply fluid line to the line of the brake unit to free fluid under pressure from the supply line to flow to the brake unit, and closing the exhaust fluid line, means operated by the lever of the lever operable clutch when operated into connecting position to close the electrical circuit of the solenoid valve to cause operation of the valve to close the supply fluid line to the brake unit line and to open the exhaust fluid line to the brake unit line to render the brake unit inactive and remove the braking force from the shaft, a normally closed pressure switch connected to the brake unit fluid line and operable into open position by fluid under pressure in said line, and means actuated by the closing of the pressure switch to close the electrical circuit to the motor.

3. A safety control for a material working machine having a drive shaft connected by a lever operable clutch to a motor, disposed in an electrical circuit, to drive the shaft normally at an operating speed when the clutch is operated into connecting position, the safety control comprising a normally inactive brake unit for the drive shaft adapted to be actuated by fluid under pressure to apply a braking force to the shaft to stop the shaft, a supply line for a fluid under pressure, an exhaust fluid line, a line to direct fluid under pressure to and from the brake unit, a solenoid valve, disposed in an electrical circuit, when unoperated opening the supply fluid line to the line of the brake unit to free fluid under pressure from the supply line to flow to the brake unit, and closing the exhaust fluid line, means operated by the lever of the lever operable clutch when operated into connecting position to close the electrical circuit of the solenoid valve to cause operation of the valve to close the supply fluid line to the brake unit line and to open the exhaust fluid line to the brake unit line to render the brake unit inactive and remove the braking force fro-m the shaft, a normally closed pressure switch connected to the brake unit fluid line and operable into open position by fluid under pressure in said line, means actuated by the closing of the pressure switch to close the electrical circuit to the motor, and means actuated by variation of the speed of the shaft from the operating speed to open the electrical circuit to the solenoid valve to render the valve unoperated to cause fluid under pressure from the supply fluid line through the brake unit line to open the pressure switch, to open the circuit to the motor, and actuate the brake unit to stop the shaft.

4. A safety control for a material working machine having a drive shaft connected by a lever operable clutch to a motor disposed in an electrical circuit to drive the shaft normally at an operating speed when the clutch is operated into connecting position, the safety control comprising a normally inactive brake unit for the drive shaft adapted to be actuated by fluid under pressure to apply a braking force to the shaft to stop the shaft, a supply line for a fluid under pressure, an exhaust fluid line, a line to direct fluid under pressure to and from the brake unit, a solenoid valve, disposed in an electrical circuit, when unoperated opening the supply fluid line to the line of the brake unit to free fluid under pressure from the supply line to flow to the brake unit, and closing the exhaust fluid line, means operated by the lever of the lever operable clutch when operated into connecting position to close the electrical circuit of the solenoid valve to cause operation of the valve to close the supply fluid line to the brake unit line and to open the exhaust fluid line to the brake unit line to render the brake unit inactive and remove the braking force from the shaft, a normally closed pressure switch connected to the brake unit fluid line and operable into open position by fluid under pressure in said line, means actuated by the closing of the pressure switch to close the electrical circuit to the motor, and a centrifugal switch driven by the shaft and adapted to open the electrical circuit to the solenoid valve when the speed of the shaft is slower than said operating speed to render the valve unoperated to cause fluid under pressure from the supply fluid line through the brake unit line to open the pressure switch, to open the circuit to the motor, and actuate the brake unit to stop the shaft.

References Cited in the file of this patent UNITED STATES PATENTS 1,319,008 King et a1. Oct. 14, 1919 1,475,121 Jones Nov. 20, 1923 1,982,354 Rowley Nov. 27, 1934 2,174,018 Schaurn Sept. 26, 1939 2,323,208 Eaton June 29, 1943 2,525,461 Schnell Oct. 10, 1950 2,678,416 Shewmon May 11, 1954 2,691,127 Oliwa Oct. 5, 1954 

